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Study on the Safety and Effectiveness of CTX001 for Children with Transfusion-Dependent Beta-Thalassemia Using Exagamglogene Autotemcel and a Drug Combination

Verified siteRegistered drugNo placebo
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What is this trial about?

A plain-language summary of the goals, design and what participants do

This clinical trial is focused on studying a condition known as Transfusion-Dependent β-Thalassemia, a blood disorder that requires regular blood transfusions. The study is evaluating a new treatment called CTX001, which involves using a technique known as CRISPR-Cas9 gene editing. This technique modifies the patient's own blood stem cells to help them produce a type of hemoglobin that can reduce or eliminate the need for blood transfusions.

The purpose of the study is to assess the safety and effectiveness of a single dose of CTX001 in children with this condition. Participants will receive a dose of their own modified stem cells, which have been altered to improve their ability to produce hemoglobin. The study will monitor the participants over time to see if they can maintain healthy hemoglobin levels without needing transfusions.

In addition to CTX001, the study involves other medications such as Filgrastim, Busulfan, and Plerixafor, which are used to prepare the body for the treatment and support the process. The study will take place over several years, with regular check-ups to ensure the safety and effectiveness of the treatment. Participants will be closely monitored for any side effects or changes in their condition.

The research process

The trial runs in 6 steps – from screening to follow-up. Each step says what happens and what the team monitors.

  1. Step 1

    Initial assessment

    The trial begins with an initial assessment to confirm eligibility. This includes a diagnosis of transfusion-dependent thalassemia (TDT) and a history of regular red blood cell (RBC) transfusions.

    A confirmation of the genotype using the study central laboratory is required before proceeding to the next step.

  2. Step 2

    Stem cell collection

    Eligible participants undergo a procedure to collect their own stem cells. This is known as an autologous stem cell transplant.

    The collected stem cells are modified using a technique called CRISPR-Cas9 to create CTX001, which is intended to treat TDT.

  3. Step 3

    Conditioning treatment

    Before receiving CTX001, a conditioning treatment with busulfan is administered. This is done to prepare the body for the new stem cells.

    Busulfan is given through an intravenous route, which means it is delivered directly into the bloodstream.

  4. Step 4

    Administration of CTX001

    After conditioning, the modified stem cells (CTX001) are infused back into the participant's body.

    This is a single-dose treatment aimed at reducing the need for future RBC transfusions.

  5. Step 5

    Post-infusion monitoring

    Following the infusion, participants are monitored for safety and efficacy. This includes regular check-ups and laboratory tests to assess health and response to treatment.

    The primary goal is to achieve transfusion independence for at least 12 consecutive months, known as TI12.

  6. Step 6

    Follow-up assessments

    Participants continue to be evaluated for secondary outcomes, such as reduction in annualized transfusions and genetic modifications in blood cells.

    Safety is assessed through monitoring of adverse events, vital signs, and laboratory values.

Who can join the trial?

7 criteria

  • The patient must have a diagnosis of **Transfusion-Dependent Thalassemia (TDT)**. This means they have a specific type of blood disorder that requires regular blood transfusions.
  • The patient must have a documented genetic condition called **homozygous or compound heterozygous β-thalassemia**, which includes a type called **β-thalassemia/hemoglobin E (HbE)**. This will be confirmed by a special laboratory test before starting treatment.
  • The patient must have a history of receiving at least 100 milliliters of **packed red blood cells (RBCs)** per kilogram of body weight each year for the past two years. Packed RBCs are a type of blood transfusion.
  • If the patient started transfusion therapy less than two years ago, they must have needed packed RBC transfusions at least every 3 to 4 weeks for at least 6 months.
  • The patient must be eligible for a **stem cell transplant** using their own cells, as determined by the doctor in charge of the study. A stem cell transplant is a procedure where healthy cells are used to replace damaged or diseased cells.
  • The patient must be between the ages of 2 and 18 years old.
  • Both male and female patients can participate in the study.

Who cannot join the trial?

4 criteria

  • Patients who are not dependent on blood transfusions cannot participate.
  • Patients who are not children cannot participate.
  • Patients who do not have a condition called **Thalassemia** cannot participate. **Thalassemia** is a blood disorder that affects the body's ability to produce hemoglobin, which is important for carrying oxygen in the blood.
  • Patients who are not able to receive a treatment involving their own modified stem cells cannot participate. **Stem cells** are special cells in the body that can develop into different types of cells.
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Investigated drugs

CTX001 is a therapy that involves using a patient's own blood stem cells, which are modified using a technology called CRISPR-Cas9. This modification aims to help the body produce healthy blood cells, reducing or eliminating the need for blood transfusions in children with a condition called transfusion-dependent β-thalassemia.

What is already known about the treatment

CTX001 – CTX001 is administered as a single dose of autologous CRISPR-Cas9 modified CD34+ human hematopoietic stem and progenitor cells. It is currently being studied in clinical trials, specifically in a Phase 3 study, to assess its safety and efficacy in treating pediatric patients with transfusion-dependent beta-thalassemia. The main therapeutic indication for CTX001 is transfusion-dependent thalassemia, a condition requiring regular blood transfusions. At the molecular level, CTX001 works by using CRISPR-Cas9 technology to edit the patient's own stem cells, aiming to correct the genetic defect causing the disease. It falls under the pharmacological classification of gene therapy products.

Investigated diseases

Transfusion-Dependent Thalassemia – This is a genetic blood disorder characterized by the body's inability to produce enough hemoglobin, which is essential for carrying oxygen in the blood. As a result, individuals with this condition often require regular blood transfusions to manage their symptoms and maintain adequate hemoglobin levels. The disease is caused by mutations in the genes responsible for hemoglobin production, leading to ineffective red blood cell formation. Over time, the need for frequent transfusions can lead to complications such as iron overload in the body. The condition is typically diagnosed in childhood and requires ongoing medical management to address the symptoms and prevent complications.
Trial detailsLast updated 7 Oct 2026
Age0-17PhasePhase IIITrial ID2024-513349-35-00Protocol codeVX21-CTX001-141Estimated enrolment16 patientsSponsorVertex Pharmaceuticals Inc.

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